Bioprosthetic heart valves have been used since the 1960s, starting with the use of homograft aortic valves obtained from human cadavers. Today prosthetic heart valves are used widely, and bioprostheses account for close to 40% of all heart-valve replacements. Although most bioprosthesis are still stented porcine aortic valves, the introduction of stentless valves and the increasing use of cryopreserved homograft valves has led to an upsurge of interest in bioprosthesis. There have been significant changes in the handling and fixation of porcine aortic valves; however, their modes of failure remain virtually unchanged, although many bioprosthetic valves now last for considerably longer periods. This article reviews the modes of failure of bioprosthetic heart valves.